I got around to doing this today if anyone else is wondering about the difference. Although there is some minor vigenatting in the faster scope with any filter it's only minor. When you look at the difference between 2inch and 36mm filters, the 48mm filters are mounted so have a clear aperture of 43mm while 36mm filters are unmounted and should have a clear aperture of 34mm which is only a couple of mm difference all round.
I saw no difference at all @ F8, but here's what ccdinspector says about the flats from the newt @ F3.8.
1st is no filter, 2nd is 2inch and 3rd is 36mm which was aproximated with a carboard mask inside a 2inch filter.
I also found I have a bit of tilt in the camera and it looks like this newt needs a tune up